Method for determining power grid phase sequence of power converter, and controller and system

Abstract

The present disclosure relates to a method for determining a power grid phase sequence of a power converter, and a controller and a system. The method in one aspect is applied to a first controller, and comprises: when all single-phase power converters are in a grid-connected power generation state, controlling remaining phase circuits in a multi-phase power grid system to be disconnected from corresponding single-phase power converters; sending a first state query request to each single-phase power converter; and on the basis of received first feedback information corresponding to the first state query request, determining a single-phase power converter, a power grid phase sequence of which is a target phase circuit, wherein the target phase circuit corresponds to any phase circuit in the multi-phase power grid system, and the remaining phase circuits correspond to phase circuits in the multi-phase power grid system other than the target phase circuit.

Description

Power converter grid phase sequence determination method, controller and system

[0001] Related applications

[0002] This disclosure claims priority to Chinese patent application filed on December 3, 2024, application number 2024117716597, entitled "Power Converter Power Grid Phase Sequence Determination Method, Controller and System", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of communication technology, and in particular to a method, controller and system for determining the power grid phase sequence of a power converter. Background Technology

[0004] In a three-phase photovoltaic system, multiple single-phase power converters (such as microinverters) are connected to the first, second, and third phases of the three-phase power grid. To improve power generation efficiency or balance the three-phase output, it is necessary to accurately determine the phase sequence of each single-phase power converter in the three-phase power grid system, that is, to determine which phase circuit each single-phase power converter is connected to, so as to facilitate individual control of the single-phase power converter corresponding to each phase circuit.

[0005] However, because the physical distance between the phase lines is very short, crosstalk may occur between the phases when the single-phase power converter communicates with the controller. Therefore, when determining the phase sequence of the single-phase power converter in a three-phase power grid system, the controller cannot accurately distinguish the signals from each phase, resulting in low accuracy of the phase sequence determination results for each single-phase power converter. Summary of the Invention

[0006] Therefore, it is necessary to provide a highly accurate power grid phase sequence determination method, controller, and system for power converters to address the aforementioned technical problems.

[0007] In a first aspect, this disclosure provides a method for determining the grid phase sequence of a power converter. The method is used by a first controller to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. The method includes:

[0008] When all single-phase power converters are in the grid-connected power generation state, the remaining phase circuits in the multi-phase power grid system are disconnected from the corresponding single-phase power converters.

[0009] Send a first status query request to each single-phase power converter;

[0010] Based on the first feedback information received corresponding to the first state query request, the single-phase power converter with the grid phase sequence as the target phase circuit is determined.

[0011] The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, while the other phase circuits correspond to all phase circuits in the multiphase power grid system except for the target phase circuit.

[0012] In one embodiment, the communication method between the first controller and each single-phase power converter includes wireless communication or power line carrier communication.

[0013] Based on the first feedback information received corresponding to the first state query request, the single-phase power converter that determines the grid phase sequence as the target circuit includes:

[0014] The grid phase sequence of the single-phase power converter, which includes the first feedback information and the first state information, is determined as the target phase circuit. The first state information is used to indicate that the corresponding single-phase power converter is in the working state.

[0015] The grid phase sequence of the single-phase power converter, which includes the first feedback information and the second state information, is determined to be not the target phase circuit. The second state information is used to indicate that the corresponding single-phase power converter is not in operation.

[0016] In one embodiment, the communication method between the first controller and each single-phase power converter includes a one-to-one wired communication method;

[0017] Based on the first feedback information received corresponding to the first state query request, a single-phase power converter that determines the grid phase sequence as the target phase circuit includes:

[0018] The grid phase sequence of the single-phase power converter that provides the first feedback information is determined as the target phase circuit.

[0019] In one embodiment, the multiphase power grid system is a three-phase power grid system, the target phase circuit includes a first phase circuit, and the remaining phase circuits include a second phase circuit and a third phase circuit.

[0020] Disconnecting the remaining phase circuits in a multiphase power grid system from their corresponding single-phase power converters includes: disconnecting the second-phase circuit and the third-phase circuit from their corresponding single-phase power converters;

[0021] Based on the first feedback information received corresponding to the first state query request, a single-phase power converter that determines the grid phase sequence as the target phase circuit includes:

[0022] Based on the first feedback information, the power grid phase sequence is determined to be that of a single-phase power converter of the first phase circuit.

[0023] In one embodiment, after determining the single-phase power converter whose grid phase sequence is the target phase circuit based on the first feedback information received corresponding to the first state query request, the method further includes:

[0024] The control circuits for the second and third phases are connected to the corresponding single-phase power converters.

[0025] When all single-phase power converters are in the grid-connected power generation state, the control first-phase circuit and the third-phase circuit are disconnected from the corresponding single-phase power converters;

[0026] Send a second state query request to each single-phase power converter whose grid phase sequence is not the first phase circuit;

[0027] Based on the second feedback information received corresponding to the second state query request, the single-phase power converter with the grid phase sequence of the second phase circuit is determined.

[0028] In one embodiment, after determining the single-phase power converter with the grid phase sequence of the second phase circuit based on the received second feedback information corresponding to the second state query request, the method further includes:

[0029] The control circuits for the first and third phases are connected to the corresponding single-phase power converters.

[0030] When all single-phase power converters are in the grid-connected power generation state, the control first phase circuit and the second phase circuit are disconnected from the corresponding single-phase power converters.

[0031] Send a third state query request to each single-phase power converter whose grid phase sequence is not the first phase circuit or the second phase circuit;

[0032] Based on the third feedback information received corresponding to the third state query request, the single-phase power converter with the grid phase sequence of the third phase circuit is determined.

[0033] In one embodiment, after determining the single-phase power converter with the grid phase sequence of the second phase circuit based on the received second feedback information corresponding to the second state query request, the method further includes:

[0034] The grid phase sequence of a single-phase power converter whose grid phase sequence is not the first or second phase circuit is determined as the third phase.

[0035] In one embodiment, the following steps are used to determine whether all single-phase power converters are in a grid-connected power generation state:

[0036] Send a fourth state query request to all single-phase power converters;

[0037] If the first quantity equals the second quantity, then all single-phase power converters are determined to be in the grid-connected power generation state; the first quantity is the number of fourth feedback messages corresponding to the fourth state query request received within a preset time period, and the second quantity is the number of single-phase power converters connected to the multiphase power grid system.

[0038] If the first quantity is not equal to the second quantity, then it is determined that not all single-phase power converters are in a grid-connected power generation state.

[0039] Secondly, this disclosure provides a method for determining the grid phase sequence of a power converter. The method is used in a first controller, which is communicatively connected to a second controller. The second controller controls the switching between corresponding phase circuits of each single-phase power converter and the multi-phase power grid system. The method is used to determine the grid phase sequence corresponding to each single-phase power converter connected to the multi-phase power grid system. The method includes:

[0040] When all single-phase power converters are in the grid-connected power generation state, a first control signal is sent to the second controller. The first control signal is used to enable the second controller to open the remaining switches.

[0041] Send a first status query request to each single-phase power converter;

[0042] Based on the first feedback information received corresponding to the first state query request, the single-phase power converter with the grid phase sequence as the target phase circuit is determined.

[0043] Among them, the remaining switches are used to control the on / off of the single-phase power converter and the remaining phase circuits corresponding to the remaining phase circuits in the multiphase power grid system. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the remaining phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit.

[0044] Thirdly, this disclosure provides a method for determining the grid phase sequence of a power converter. The method is used in a second controller, which controls the switching between corresponding phase circuits of each single-phase power converter and the multi-phase grid system. The method is used to determine the grid phase sequence corresponding to each single-phase power converter connected to the multi-phase grid system. The method includes:

[0045] When all single-phase power converters are in the grid-connected power generation state, the first control signal sent by the first controller is received;

[0046] Based on the first control signal, the remaining switches are opened so that when the target switch is closed and the remaining switches are open, the first controller sends a first state query request to each single-phase power converter and determines the single-phase power converter of the target phase circuit based on the first feedback information corresponding to the received first state query request.

[0047] The target switch is used to control the on / off state of the single-phase power converter and the target phase circuit corresponding to the target phase circuit in the multiphase power grid system. The other switches are used to control the on / off state of the single-phase power converter and the other phase circuits corresponding to the other phase circuits in the multiphase power grid system. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the other phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit.

[0048] Fourthly, this disclosure provides a first controller, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the methods as described in the first and / or second aspects.

[0049] In one embodiment, the first controller includes a switching module, and the process of the processor disconnecting the remaining phase circuits in the multiphase power grid system from the corresponding single-phase power converter includes: the processor controlling the remaining phase circuits to disconnect from the corresponding single-phase power converter through the switching module.

[0050] Fifthly, this disclosure provides a second controller, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the method as described in the third aspect.

[0051] Sixthly, this disclosure provides a power system comprising: multiple single-phase power converters, relays, and a first controller; wherein,

[0052] The first terminal of the target switch in the relay is connected to the controller and the target phase circuit for connecting the multiphase power grid system. The second terminal of the target switch is connected to the single-phase power converter corresponding to the target phase circuit. The first terminal of the other switches in the relay is connected to the gateway controller and the other phase circuits for connecting the multiphase power grid system. The second terminal of the other switches is connected to the single-phase power converter corresponding to the other phase circuits. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the other phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit.

[0053] The gateway control includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the methods as described in the first aspect and / or the second aspect.

[0054] The aforementioned method, controller, and system for determining the grid phase sequence of power converters include a method used in a first controller to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. This involves controlling the disconnection of the remaining phase circuits and corresponding single-phase power converters in the multiphase power grid system while all single-phase power converters are in a grid-connected state, sending a first state query request to each single-phase power converter, and determining the single-phase power converter whose grid phase sequence corresponds to the target phase circuit based on the received first feedback information corresponding to the first state query request. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the remaining phase circuits correspond to all phase circuits in the multiphase power grid system except the target phase circuit. In this way, assuming all single-phase power converters connected to the multiphase power grid system are able to generate electricity normally, the connection between the target phase circuit and its corresponding single-phase power converter is maintained, while the connections between the remaining phase circuits and their corresponding single-phase power converters are disconnected. This ensures that when the multiphase power grid system is in a state where only one phase circuit is connected to its corresponding single-phase power converter, and the remaining phase circuits do not transmit power, the operating status of each single-phase power converter is actively queried. Based on the feedback information from the single-phase power converters, the grid phase sequence of the single-phase power converters is determined, avoiding the impact of communication crosstalk between phase circuits on the accuracy of grid phase sequence identification. Using the above grid phase sequence determination method can improve the accuracy of grid phase sequence identification when single-phase power converters are connected to the multiphase power grid system, thereby improving the initial efficiency of single-phase power converter grid connection. By using the above grid phase sequence determination method, the grid phase sequence of each single-phase power converter is accurately identified, thus supporting precise power control of each phase circuit and improving the power generation revenue of the power system. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments or conventional technologies of this disclosure, the accompanying drawings used in the description of the embodiments or conventional technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the disclosed drawings without creative effort.

[0056] Figure 1 is an application environment diagram of the power grid phase sequence determination method in one embodiment;

[0057] Figure 2 shows the application environment of the power grid phase sequence determination method in another embodiment;

[0058] Figure 3 is a flowchart illustrating a power grid phase sequence determination method in one embodiment;

[0059] Figure 4 is a flowchart illustrating the power grid phase sequence determination method in another embodiment;

[0060] Figure 5 is a flowchart illustrating the process of determining whether all single-phase power converters are in grid-connected power generation state in one embodiment.

[0061] Figure 6 is a flowchart illustrating the power grid phase sequence determination method in another embodiment;

[0062] Figure 7 is a flowchart illustrating the power grid phase sequence determination method in another embodiment. Detailed Implementation

[0063] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure.

[0065] It is understood that the terms "first," "second," etc., as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0066] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0067] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0068] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0069] The power converters disclosed in this embodiment are power conversion devices used to convert electrical energy from one form to another, realizing energy transmission and control under different power requirements. Power converters can be microinverters, energy storage converters, etc. For example, a microinverter can convert DC power to AC power. The DC input of the microinverter is connected to a DC source (photovoltaic module), and the AC output can be connected to an AC power grid and AC equipment. A single-phase power converter refers to a converter with a single-phase output or single-phase input on the AC side, connected to one phase of the AC power grid or AC equipment. A single-phase power converter can be a single-phase microinverter, a single-phase energy storage converter, etc.

[0070] In an exemplary embodiment, the provided power converter grid phase sequence determination method can be applied to the application environment shown in Figure 1 or Figure 2. Referring to Figures 1 and 2, multiple single-phase power converters are respectively connected to the first phase circuit, second phase circuit, or third phase circuit of a three-phase power grid system. These multiple single-phase power converters can be considered as a single-phase power converter array. The gateway controller acts as the control center of this array, connecting to each phase circuit and the zero-phase circuit of the three-phase power grid system, and communicating with each single-phase power converter to monitor the operating status of all single-phase power converters and control their output. This achieves precise power control of each phase circuit of the three-phase power grid system and allows the transmission of device data from each single-phase power converter to the management system and cloud network management via communication methods such as FE (Fast Ethernet), WLAN (Wireless Local Area Network), 4G, or 5G. In other embodiments, other types of controllers can also communicate with and control the switching of each single-phase power converter and the multi-phase power grid system.

[0071] For example, in Figures 1 and 2, the three lines connected to the switch represent the three live phase wires 100 of the three-phase power grid system, and the remaining line represents the neutral wire 200 (or neutral line) of the three-phase power grid system. The cylinder represents the conduit 300 outside the three live phase wires 100 and the neutral wire 200, that is, the four phase wires are located in one cable. It should be noted that when the single-phase power converters shown in Figures 1 and 2 are connected to the corresponding phase circuits in the field, the gateway controller does not obtain the wiring relationship at this time.

[0072] In the application environment example shown in Figure 1, the gateway controller includes a processor and a switching module. The processor communicates with the single-phase power converters, and the switching module controls the connection or disconnection between each single-phase power converter and its corresponding phase circuit in the three-phase power grid system. The switching module can individually control the on / off state of each single-phase power converter and its corresponding phase circuit. Optionally, the switching module is a multi-pole multi-throw (MPLT) structure. It is understood that the gateway controller in Figure 1 is a gateway controller with integrated relays.

[0073] In the application environment example shown in Figure 2, a separate relay is set up, and the gateway controller controls the connection or disconnection between each single-phase power converter and the corresponding phase circuit of the three-phase power grid system through the relay.

[0074] In this embodiment, the power grid phase sequence is used to characterize which phase of a three-phase power grid system the single-phase power converter is connected to—the first, second, or third phase. During the wiring process of connecting the single-phase power converter to the three-phase power grid system, this power grid phase sequence is not pre-configured in the gateway controller. In related technologies, when determining the power grid phase sequence of a single-phase power converter, because all phase lines are located within the same conduit and the physical distance between them is very short, communication crosstalk may occur between the single-phase power converters connected to each phase circuit, resulting in low accuracy of the determined power grid phase sequence. Therefore, this embodiment provides a method for determining the power grid phase sequence of a power converter.

[0075] In one exemplary embodiment, the power grid phase sequence determination method for the provided power converter can also be applied to other multiphase power grid systems, such as two-phase power grid systems, and is not limited to three-phase power grid systems.

[0076] In an exemplary embodiment, as shown in FIG3, a method for determining the grid phase sequence of a power converter is provided, used in a first controller. The method is used to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. The first controller can be a gateway controller, or other controllers capable of communicating with each single-phase power converter and controlling the on / off states of each single-phase power converter and the multiphase power grid system. For example, in the case where the multiphase power grid system is a three-phase power grid system, the first controller can be the gateway controller shown in FIG1 or FIG2. In this embodiment, the method includes steps 302 to 306, wherein:

[0077] Step 302: When all single-phase power converters are in the grid-connected power generation state, control the remaining phase circuits in the multi-phase power grid system to disconnect from the corresponding single-phase power converters.

[0078] In this embodiment, although the first controller cannot determine the grid phase sequence of each single-phase power converter, it can determine the total number of single-phase power converters in the multi-phase power grid system.

[0079] In this process, after the first controller is activated, it connects all single-phase power converters to their corresponding phase circuits, ensuring that each phase circuit is connected to its corresponding single-phase power converter to verify that each single-phase power converter is functioning correctly. Only after confirming that all single-phase power converters are in grid-connected power generation mode does the determination of the grid phase sequence for each single-phase power converter begin. This prevents inaccurate determination of the overall grid phase sequence if a single single-phase power converter malfunctions.

[0080] In this embodiment, each phase circuit in the multiphase power grid system is divided into a target phase circuit and other phase circuits. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the other phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit.

[0081] In one possible implementation, the multiphase power grid system is a three-phase power grid system, which includes a first-phase circuit, a second-phase circuit, and a third-phase circuit; the target phase circuit can be the first-phase circuit, and the remaining circuits can be the second-phase and third-phase circuits. In this implementation, after the first controller is activated, the first-phase circuit, the second-phase circuit, and the third-phase circuit are all connected to their corresponding single-phase power converters to determine whether each single-phase power converter can operate normally.

[0082] In one possible implementation, the multiphase power grid system is a two-phase power grid system; the two-phase power grid system includes a first-phase circuit and a second-phase circuit, the target phase circuit can be the first-phase circuit, and the remaining phase circuits can be the second-phase circuits. In this implementation, after the first controller is activated, it connects both the first-phase circuit and the second-phase circuit to their corresponding single-phase power converters to determine whether each single-phase power converter can operate normally.

[0083] Specifically, the control circuits of the other phases are disconnected from the corresponding single-phase power converters, so that each single-phase power converter corresponding to the other phases changes from being in a generating state to being in a non-generating state. At this time, only the single-phase power converter corresponding to the target phase circuit is in a generating state, which can avoid power transmission on the other phases and prevent crosstalk between the single-phase power converter connected to the target phase circuit and the first controller.

[0084] For example, being in a non-power-generating state includes being in a standby state or a fault state.

[0085] In one possible implementation, the processor in the first controller controls all single-phase power converters to connect to their corresponding phase circuits via a switching module; after determining that all single-phase power converters are in a grid-connected power generation state, the processor controls the remaining phase circuits in the multiphase power grid system to disconnect from their corresponding single-phase power converters via the switching module.

[0086] Step 304: Send a first status query request to each single-phase power converter.

[0087] The status query request is used to provide feedback on the current operating status of the single-phase power converter based on the status query request; the first status query request refers to the status query request sent by the first controller to all single-phase power converters. Optionally, the current operating status of the single-phase power converter may include a status identifier code maintained by the single-phase power converter based on its own operating status. For example, a status identifier code of "00" indicates that the single-phase power converter is currently in standby mode, a status identifier code of "01" indicates that the single-phase power converter is currently in operating mode, and a status identifier code of "11" indicates that the single-phase power converter is currently in fault mode. Optionally, the current operating status of the single-phase power converter may include the current power generation of the single-phase power converter. For example, when the single-phase power converter is connected to the corresponding phase circuit in the multi-phase power grid system, the power generation is 5500 watts (W); when the single-phase power converter is disconnected from the corresponding phase circuit in the multi-phase power grid system, the power generation is 0W.

[0088] In one possible implementation, the first controller broadcasts a first state query request to all single-phase power converters via a broadcast.

[0089] Step 306: Based on the first feedback information received corresponding to the first state query request, determine the single-phase power converter of the target phase circuit in the power grid phase sequence.

[0090] The first feedback information refers to the feedback information generated by the single-phase power converter based on the first state query request, including the current operating state of the single-phase power converter. For example, when the single-phase power converter is in a generating state, the feedback information includes a state identifier code corresponding to the operating state; when the single-phase power converter is in a non-generating state, the feedback information includes a state identifier code corresponding to the standby state or fault state. Optionally, the feedback information may also include the current generating power of the single-phase power converter. It is understood that when the single-phase power converter is in a standby state or a fault state, the generating power in the feedback information is 0.

[0091] When the target phase circuit is connected to the corresponding single-phase power converter, and the other phase circuits are disconnected from the corresponding single-phase power converters, only the single-phase power converter connected to the target phase circuit is in a power generation state, i.e., in an operating state and generating power. The single-phase power converters connected to the other phase circuits will not respond to the first state query request, i.e., they will not send the first feedback information, or the first feedback information from the single-phase power converters connected to the other phase circuits includes a non-operating state. Therefore, based on the received first feedback information, the first controller can identify the single-phase power converters connected to the target phase circuit and determine the grid phase sequence of these single-phase power converters connected to the target phase circuit as the target phase circuit.

[0092] In a first possible implementation of this embodiment, after identifying the single-phase power converter connected to the target phase circuit, the first controller controls the remaining phase circuits to connect to the corresponding single-phase power converters, re-determines one phase circuit from the remaining phase circuits as the current target phase circuit, and then determines the phase circuits other than the current target phase circuit as the remaining phase circuits. The process of "controlling the remaining phase circuits in the multiphase power grid system to disconnect from the corresponding single-phase power converters when all the single-phase power converters are in the grid-connected power generation state; sending a first status query request to each single-phase power converter; determining the grid phase sequence as the single-phase power converter of the target phase circuit according to the first feedback information received corresponding to the first status query request" is repeated until all phase circuits in the multiphase power grid system are used as target phase circuits and the grid phase sequence corresponding to the corresponding single-phase power converter is determined.

[0093] Understandably, in the first embodiment described above, the first controller is equivalent to repeatedly executing the steps shown in steps 302 to 306 multiple times. During each execution, the phase circuit that is currently in the connected state is changed, and the remaining phase circuits are shut down. During each execution, a first state query request is sent to all single-phase power converters to identify the single-phase power converters corresponding to the remaining phase circuits.

[0094] In the first application scenario of the first embodiment described above, the multiphase power grid system is a three-phase power grid system, which includes a first-phase circuit, a second-phase circuit, and a third-phase circuit. During the first identification, the second-phase and third-phase circuits are disconnected from their corresponding single-phase power converters, identifying the single-phase power converter with the first-phase power converter in the grid phase sequence. During the second identification, the second-phase and third-phase circuits are connected to their corresponding single-phase power converters. When all the single-phase power converters are in a grid-connected power generation state, the first-phase and third-phase circuits are disconnected from their corresponding single-phase power converters; power is supplied to each of the single-phase power converters... The power converter sends a first state query request; based on the first feedback information received corresponding to the first state query request, it determines that the single-phase power converter with the grid phase sequence is the second phase circuit; then, it controls the first phase circuit and the third phase circuit to be linked with the corresponding single-phase power converter; when all single-phase power converters are in the grid-connected power generation state, it controls the first phase circuit and the second phase circuit to be disconnected from the corresponding single-phase power converter, sends a first state query request to each single-phase power converter, and determines that the single-phase power converter with the grid phase sequence is the third phase circuit based on the first feedback information received corresponding to the first state query request.

[0095] In the second application scenario of the first embodiment described above, the multiphase power grid system is a two-phase power grid system, which includes a first-phase circuit and a second-phase circuit. After identifying the single-phase power converter connected to the first-phase circuit, the second-phase circuit is controlled to connect to the corresponding single-phase power converter. When all the single-phase power converters are in the grid-connected power generation state, the first-phase circuit is controlled to disconnect from the corresponding single-phase power converter. A first status query request is sent to each of the single-phase power converters. Based on the first feedback information received corresponding to the first status query request, the single-phase power converter of the second-phase circuit is determined to be part of the grid phase sequence.

[0096] In other application scenarios of the first embodiment described above, the multiphase power grid system can correspond to a multiphase power grid system other than a two-phase power grid system or a three-phase power grid system. The specific implementation process can refer to the implementation methods of the three-phase power grid system or the two-phase power grid system, and will not be repeated here.

[0097] In a second possible implementation of this embodiment, after identifying the single-phase power converter connected to the target phase circuit, during the process of identifying the single-phase power converter connected to the other phase circuits, subsequent status query requests are no longer sent to the single-phase power converters whose grid phase sequence has been determined, so as to improve identification efficiency.

[0098] In the first application scenario of the second implementation, the multiphase power grid system is a three-phase power grid system, which includes a first-phase circuit, a second-phase circuit, and a third-phase circuit. In steps 302 to 306, the target phase circuit includes the first-phase circuit, and the remaining phase circuits include the second-phase circuit and the third-phase circuit. The process of controlling the remaining phase circuits in the multiphase power grid system to disconnect from the corresponding single-phase power converter in step 302 includes: controlling the second-phase circuit and the third-phase circuit to disconnect from the corresponding single-phase power converter. The process of determining the single-phase power converter with the grid phase sequence as the target phase circuit based on the first feedback information received corresponding to the first status query request in step 306 includes: determining the single-phase power converter with the grid phase sequence as the first phase circuit based on the first feedback information. In this example, after step 306, the single-phase power converter with the grid phase sequence as the second phase circuit is determined according to steps 402 to 408 as shown in Figure 4.

[0099] Step 402: Control the connection of the second-phase circuit and the third-phase circuit to the corresponding single-phase power converter.

[0100] Step 404: When all single-phase power converters are in the grid-connected power generation state, control the first phase circuit and the third phase circuit to disconnect from the corresponding single-phase power converters.

[0101] Step 406: Send a second state query request to each single-phase power converter whose grid phase sequence is not the first phase circuit.

[0102] The second state query request refers to the request recipients only including each single-phase power converter whose grid phase sequence is not the first phase circuit. The difference between the second state query request and the first state query request in step 304 is that the recipients of the request are not all the same. The recipients of the first state query request include all single-phase power converters controlled by the gateway controller, while the recipients of the second state query request do not include single-phase power converters whose grid phase sequence has been determined to be the first phase circuit.

[0103] Step 408: Based on the second feedback information received corresponding to the second state query request, determine that the power grid phase sequence is a single-phase power converter of the second phase circuit.

[0104] The second feedback information refers to the feedback information made by the single-phase power converter based on the second state query request.

[0105] In the first application scenario of the second embodiment described above, after determining that the single-phase power converter with the grid phase sequence is the second phase circuit, the single-phase power converter with the grid phase sequence is the third phase can be determined according to the implementation method shown in steps 410 to 416 of Figure 4, wherein steps 410 to 416 include:

[0106] Step 410: Control the connection of the first phase circuit and the third phase circuit to the corresponding single-phase power converter.

[0107] Step 412: When all single-phase power converters are in the grid-connected power generation state, control the first phase circuit and the second phase circuit to disconnect from the corresponding single-phase power converters.

[0108] Step 414: Send a third state query request to each single-phase power converter whose grid phase sequence is neither the first phase circuit nor the second phase circuit.

[0109] The third state query request refers to a request whose recipients only include single-phase power converters whose grid phase sequence is not the first or second phase. The difference between this request and the first and second state query requests is that the recipients are not all the same.

[0110] Step 416: Based on the third feedback information received corresponding to the third state query request, determine the single-phase power converter with the grid phase sequence of the third phase circuit.

[0111] In the first application scenario of the second embodiment described above, after determining that the single-phase power converter with the grid phase sequence is the second phase circuit, the grid phase sequence of the single-phase power converter that is neither the first phase circuit nor the second phase circuit can be directly determined as the third phase circuit. In this way, based on the single-phase power converters corresponding to the two phase circuits that have already been determined, the single-phase power converter corresponding to the remaining phase circuit can be directly determined, thereby improving the efficiency of grid phase sequence determination.

[0112] In the second application scenario of the second implementation, the multiphase power grid system is a two-phase power grid system, which includes a first-phase circuit and a second-phase circuit. For example, after identifying the single-phase power converter connected to the first-phase circuit, the second-phase circuit can be controlled to connect to the corresponding single-phase power converter. When all the single-phase power converters are in grid-connected power generation mode, the first-phase circuit is controlled to disconnect from the corresponding single-phase power converter, and a second status query request is sent to each single-phase power converter whose grid phase sequence is not the first-phase circuit. Based on the second feedback information received corresponding to the second status query request, the single-phase power converter whose grid phase sequence is the second-phase circuit is determined. Alternatively, after identifying the single-phase power converter connected to the first-phase circuit, the grid phase sequence of the single-phase power converter whose grid phase sequence is not the first-phase circuit can be directly determined as the second-phase circuit. Thus, based on the already determined single-phase power converter corresponding to the first-phase circuit, the single-phase power converter corresponding to the remaining phase circuit is directly determined, improving the efficiency of grid phase sequence determination.

[0113] In other application scenarios of the second embodiment described above, the multiphase power grid system can correspond to a multiphase power grid system other than a two-phase power grid system or a three-phase power grid system. The specific implementation process can refer to the implementation methods of the three-phase power grid system or the two-phase power grid system, and will not be repeated here.

[0114] After completing the grid phase sequence identification of all single-phase power converters, the system controls each phase circuit in the multiphase grid system to be connected to the corresponding single-phase power converter, so that all single-phase power converters can generate electricity normally.

[0115] The grid phase sequence determination method for power converters provided in the above embodiments is used in a first controller. The method is used to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. By controlling the other phase circuits and corresponding single-phase power converters in the multiphase power grid system to disconnect when all single-phase power converters are in the grid-connected power generation state, a first state query request is sent to each single-phase power converter. Based on the first feedback information received corresponding to the first state query request, the grid phase sequence of the single-phase power converter corresponding to the target phase circuit is determined. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the other phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit. In this way, when all single-phase power converters connected to the multiphase power grid system are able to generate electricity normally, the connection between the target phase circuit and its corresponding single-phase power converter is maintained, while the connections between the remaining phase circuits and their corresponding single-phase power converters are disconnected. This ensures that when the multiphase power grid system is in a state where only one phase circuit is connected to its corresponding single-phase power converter, and the remaining phase circuits do not transmit power, the operating status of each single-phase power converter is actively queried. Based on the feedback information from the single-phase power converters, the grid phase sequence of the single-phase power converters is determined, avoiding the impact of communication crosstalk between phase circuits on the accuracy of grid phase sequence identification. The grid phase sequence determination method provided in the above embodiment can improve the accuracy of grid phase sequence identification when single-phase power converters are connected to the multiphase power grid system, thereby improving the start-up efficiency of single-phase power converter grid connection. By using the grid phase sequence determination method provided in the above embodiment, the grid phase sequence of each single-phase power converter is accurately identified, thereby supporting precise power control of each phase circuit and improving the power generation revenue of the power system.

[0116] In an exemplary embodiment, the communication method between the first controller and each single-phase power converter includes wireless communication or power line communication (PLC). In this embodiment, the process of determining the grid phase sequence of a single-phase power converter as the target phase circuit based on the received first feedback information corresponding to the first status query request includes: determining the grid phase sequence of the single-phase power converter whose first feedback information includes first status information as the target phase circuit; and determining the grid phase sequence of the single-phase power converter whose first feedback information includes second status information as not the target phase circuit, wherein the first status information is used to indicate that the corresponding single-phase power converter is in an operating state, and the second status information is used to indicate that the corresponding single-phase power converter is not in an operating state.

[0117] Optionally, the first status information includes the single-phase power converter's operating status parameter being "in operating state," for example, the operating status identification code being "01." The second status information includes the single-phase power converter's operating status parameter being "in standby state" or "in fault state," for example, the operating status identification code being "10" or "11."

[0118] Optionally, the first state information includes a single-phase power converter generating power greater than 0; the second state information includes a single-phase power converter generating power of 0.

[0119] Optionally, the first state information includes the power generation of the single-phase power converter being greater than a first threshold and less than a second threshold; the second state information includes the power generation of the single-phase power converter being between the first threshold and the second threshold, wherein the range from the first threshold to the second threshold is the normal power generation range of the single-phase power converter.

[0120] When the communication between the controller and each single-phase power converter is wireless, if the other phase circuits are disconnected from their corresponding single-phase power converters, the single-phase power converters connected to the other phase circuits, although not in a generating state, can still reply with the first feedback information wirelessly. That is, all single-phase power converters will reply with the first feedback information to the first controller. The first controller determines the single-phase power converters in operation based on the content included in the first feedback information, and identifies the single-phase power converter with the target phase sequence in the power grid. If the first feedback information includes first status information, it indicates that the single-phase power converter is in operation, and its power grid phase sequence is marked as the target phase circuit. If the first feedback information includes second status information, it indicates that the single-phase power converter is not in operation, and its power grid phase sequence is determined to be not the target phase circuit.

[0121] When the communication between the first controller and each single-phase power converter is PLC, when the other phase circuits are disconnected from the corresponding single-phase power converters, the communication connection between the single-phase power converters connected to the other phase circuits and the first controller is also disconnected. Theoretically, the single-phase power converters connected to the other phase circuits will not receive or respond to the first state query request. However, as shown in Figures 1 and 2, the multiple live and neutral lines connecting each single-phase power converter are generally located in the same conduit. When using a PLC, although there is no power transmission in the remaining phase circuits disconnected from the single-phase power converter, and only one phase circuit has power transmission, the target phase circuit with power transmission will generate PLC crosstalk to the remaining phase circuits because the distance between the phase lines is very close. This causes some single-phase power converters connected to the target phase circuit to reply with the first state query request. In this embodiment, the grid-connected phase sequence of the single-phase power converter that includes the first state information (not the second state information) is determined as the target phase circuit. Since the characteristics of the first state information and the second state information are not completely the same, the first feedback information can be distinguished accordingly, thereby filtering out the first feedback information that crosstalks to the target phase circuit, excluding the corresponding single-phase power converter, and avoiding the impact of PLC crosstalk on the accuracy of the grid phase sequence determination.

[0122] In an exemplary embodiment, the communication method between the first controller and each single-phase power converter includes a one-to-one wired communication method. Exemplarily, the one-to-one wired communication method includes RS 485 (Recommended Standard 485) communication. In this embodiment, the process of determining the grid phase sequence of a single-phase power converter as the target phase circuit based on the received first feedback information corresponding to the first status query request includes: determining the grid phase sequence of the single-phase power converter that fed back the first feedback information as the target phase circuit.

[0123] In this embodiment, the first controller and each single-phase power converter communicate via a one-to-one wired communication method. When the single-phase power converter corresponding to the other phase circuit is disconnected, the communication connection between the single-phase power converter connected to the other phase circuit and the controller is also disconnected. The single-phase power converter connected to the other phase circuit will not receive or respond to the first state query request. Therefore, in this embodiment, the single-phase power converter of the target phase circuit can be determined directly based on which single-phase power converters have fed back the first feedback information.

[0124] In an exemplary embodiment, referring to Figure 5, the grid phase sequence determination method for the provided power converter determines whether all single-phase power converters are in a grid-connected power generation state according to the process shown in steps 502 to 506, wherein:

[0125] Step 502: Send a fourth state query request to all single-phase power converters.

[0126] Specifically, after controlling all phase circuits to connect to the corresponding single-phase power converters, a fourth state query request is sent to all single-phase power converters to obtain the current operating state of each single-phase power converter.

[0127] For example, the content of the fourth state query request is the same as that of the first state query request, the second state query request, and the third state query request.

[0128] Step 504: If the first quantity equals the second quantity, then it is determined that all single-phase power converters are in the state of grid-connected power generation.

[0129] The first quantity is the number of fourth feedback messages corresponding to the fourth state query request received within a preset time period, and the second quantity is the number of single-phase power converters connected to the multiphase power grid system.

[0130] In one possible implementation, within a preset time period, the first controller sends a fourth status query request to each single-phase power converter at a preset query frequency until the preset time period ends or all single-phase power converters reply with the fourth feedback information, so as to improve the efficiency of obtaining the operating status of all single-phase power converters.

[0131] In one possible implementation, the first controller sends a fourth state query request to each single-phase power converter and counts the number of single-phase power converters that respond to the fourth state query request within a preset time period; if a single-phase power converter responds to the fourth state query request after the preset time period, it is considered that the single-phase power converter is not in the grid-connected power generation state and is not counted.

[0132] Step 506: If the first quantity is not equal to the second quantity, then it is determined that not all single-phase power converters are in the grid-connected power generation state.

[0133] In cases where the first quantity is not equal to the second quantity, there may be a fault in the power generation function of some single-phase power converters, or there may be a communication fault between some single-phase power converters and the gateway controller, or other reasons. Therefore, if it is determined that not all single-phase power converters are in a grid-connected power generation state when the first quantity is not equal to the second quantity, the subsequent grid phase sequence determination method will not be executed to avoid inaccurate identification.

[0134] In an exemplary embodiment, referring to FIG6, a method for determining the grid phase sequence of a power converter is provided. This method is used in a first controller, which is communicatively connected to a second controller. The second controller controls the on / off switching between corresponding phase circuits of each single-phase power converter and the multiphase grid system. The method determines the grid phase sequence corresponding to each single-phase power converter connected to the multiphase grid system. The first and second controllers are independent of each other. The first controller can be the gateway controller shown in FIG2, and the second controller can be the switch controller in the relay shown in FIG2. It is understood that the first controller can also be other controllers capable of communicatively connecting to each single-phase power converter and controlling the on / off switching between each single-phase power converter and the multiphase grid system via an external switch. As shown in FIG6, the method includes steps 602 to 606.

[0135] Step 602: With all single-phase power converters in grid-connected power generation mode, a first control signal is sent to the second controller. This first control signal is used to instruct the second controller to open the remaining switches.

[0136] In this embodiment, the phase circuits in the multiphase power grid system are divided into target phase circuits and remaining phase circuits. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the remaining phase circuits correspond to all phase circuits in the multiphase power grid system except for the target phase circuit. The remaining switches are used to control the on / off state of the single-phase power converters and the remaining phase circuits corresponding to the remaining phase circuits in the multiphase power grid system. Correspondingly, in this embodiment, the on / off state of the single-phase power converter and the first phase circuit corresponding to the target phase circuit in the multiphase power grid system is achieved by controlling the target switch.

[0137] In one possible implementation, the multiphase power grid system is a three-phase power grid system, the target switch includes a first switch, and the remaining switches include a second switch and a third switch; a first control signal is used to enable a second controller to perform at least one action of opening the second switch or opening the third switch.

[0138] In one example of this implementation, as shown in Figure 2, a first switch, a second switch, a third switch, and a switch controller are disposed inside a relay. The switch controller can be a processor within the relay. The gateway controller controls the connection and disconnection between the corresponding phase circuit and each single-phase power converter through the relay. The first terminal of the first switch of the relay is connected to the gateway controller and the first phase circuit, and the second terminal of the first switch is connected to the single-phase power converter corresponding to the first phase circuit. The first terminal of the second switch in the relay is connected to the gateway controller and the second phase circuit, and the second terminal of the second switch is connected to the single-phase power converter corresponding to the second phase circuit. The first terminal of the third switch in the relay is connected to the gateway controller and the third phase circuit, and the second terminal of the third switch is connected to the single-phase power converter corresponding to the third phase circuit. The switch controller is used to control the on / off state of the first switch, the second switch, and the third switch. In this embodiment, when the switch controller receives a first control signal, it opens the second switch and the third switch.

[0139] Optionally, the first switch, the second switch, and the third switch are the first contact, the second contact, and the third contact in the multi-pole multi-throw structure inside the relay. Each contact is equivalent to a switch, controlling the on / off state of the circuit between the corresponding phase circuit and the single-phase power converter.

[0140] In another example of this implementation, the multiphase power grid system is a three-phase power grid system. The target switch includes a first switch, and the remaining switches include a second switch and a third switch. The first switch, the second switch, and the third switch each correspond to a switch controller. Each switch controller is connected to a gateway controller. When the switch controller corresponding to the first switch receives a first control signal, it keeps the first switch in the closed state. When the switch controller corresponding to the second switch receives the first control signal, it opens the second switch. When the switch controller corresponding to the third switch receives the first control signal, it opens the third switch.

[0141] Step 604: Send a first status query request to each single-phase power converter.

[0142] Step 606: Based on the first feedback information received corresponding to the first state query request, determine the single-phase power converter of the target phase circuit in the power grid phase sequence.

[0143] In this process, after the first controller determines that the single-phase power converter is the target phase circuit of the grid phase sequence, it sends a control signal to the second controller to close the switches between all phase circuits and the corresponding single-phase power converters, or sends a control signal to the second controller to close the remaining switches, so that all single-phase power converters can be in the grid-connected power generation state; then it executes the subsequent determination of the single-phase power converters corresponding to other grid phase sequences.

[0144] In one possible implementation, the multiphase power grid system is a three-phase power grid system. After determining that the grid phase sequence is for the single-phase power converter of the first phase circuit, the first controller sends a control signal to the second controller to close the switches between all phase circuits and the corresponding single-phase power converters, or sends a control signal to the second controller to close the second and third switches, so that all single-phase power converters can be in a grid-connected power generation state. Then, a second control signal is sent to the second controller to determine that the grid phase sequence is for the single-phase power converter of the second phase circuit. The second control signal is used to instruct the second controller to open the first switch and open the third switch. At least one action of the switch; then, after determining that the single-phase power converter of the grid phase sequence is the second phase circuit, the first controller sends a control signal to the second controller to close the switches between all phase circuits and the corresponding single-phase power converters, or sends a control signal to the second controller to close the first switch and the third switch, so that all single-phase power converters can be in the grid-connected power generation state, and then sends a third control signal to the second controller to determine that the single-phase power converter of the grid phase sequence is the target phase circuit, wherein the third control signal is used to enable the second controller to perform at least one action of opening the second switch or opening the first switch.

[0145] Optionally, the second and third control signals are pre-configured. Optionally, the second control signal is obtained by modifying the first control signal after the first controller identifies that the grid phase sequence is a single-phase power converter of the first phase circuit, and the third control signal is obtained by modifying the second control signal after the first controller identifies that the grid phase sequence is a single-phase power converter of the second phase circuit.

[0146] The power grid phase sequence determination method provided in this embodiment involves a first controller connected to a second controller. The second controller controls the connection and disconnection between each single-phase power converter and the corresponding phase circuit of the multi-phase power grid system. The first controller sends relevant control signals to the second controller, causing the second controller to connect one phase circuit in the multi-phase power grid system to the corresponding single-phase power converter, while disconnecting the remaining phase circuits from the corresponding single-phase power converters. The first controller actively queries the operating status of each single-phase power converter and determines which single-phase power converter is currently connected based on the feedback from the single-phase power converter. This process identifies the power grid phase sequence corresponding to each single-phase power converter, improving the accuracy of the power grid phase sequence determination and increasing the grid connection efficiency of the single-phase power converters.

[0147] In an exemplary embodiment, referring to FIG7, a method for determining the power grid phase sequence of a power converter is provided. Taking the application of this method to a second controller as an example, the second controller is used to control the on / off switching between the corresponding phase circuits of each single-phase power converter and the multi-phase power grid system. As shown in FIG7, the power grid phase sequence determination method provided in this embodiment includes steps 702 and 704.

[0148] Step 702: With all single-phase power converters in the grid-connected power generation state, receive the first control signal sent by the first controller.

[0149] Step 704: Based on the first control signal, the remaining switches are opened so that the first controller can send a first status query request to each single-phase power converter when the target switch is closed and the remaining switches are open, and determine the single-phase power converter of the target phase circuit based on the first feedback information corresponding to the received first status query request.

[0150] The target switch is used to control the on / off state of the single-phase power converter and the target phase circuit corresponding to the target phase circuit in the multiphase power grid system. The other switches are used to control the on / off state of the single-phase power converter and the other phase circuits corresponding to the other phase circuits in the multiphase power grid system. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the other phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit.

[0151] In one possible implementation, the multiphase power grid system is a three-phase power grid system. The target phase circuit in steps 702 and 704 corresponds to the first phase circuit, the target switch corresponds to the first switch, the remaining phase circuits correspond to the second and third phase circuits, and the remaining switches correspond to the second and third switches. Step 704, which involves opening the remaining switches based on the first control signal, includes: opening at least one of the second or third switches based on the first control signal. In this implementation, after the first controller determines that the single-phase power converter with the grid phase sequence is the first phase circuit, the second controller receives a control signal from the first controller to close the switches between all phase circuits and the corresponding single-phase power converters, or receives a control signal from the first controller to close the second and third switches. After executing the corresponding control signals, all switches are in the closed state. After the first controller determines that all single-phase power converters are in a grid-connected power generation state... The first controller receives a second control signal from the first controller and performs at least one action, either opening the first switch or opening the third switch, based on the second control signal, so that the first controller can determine that the single-phase power converter is a second-phase circuit in the power grid phase sequence. After the first controller determines that the single-phase power converter is a second-phase circuit in the power grid phase sequence, the second controller receives a control signal from the first controller to close the switches between all phase circuits and the corresponding single-phase power converters, or receives a control signal from the first controller to close the first switch and close the second switch, and executes the corresponding control signal to make all switches closed. After the first controller determines that all single-phase power converter ports are in the grid-connected power generation state, the second controller receives a third control signal from the first controller and performs at least one action, either opening the second switch or opening the first switch, based on the third control signal, so that the first controller can determine that the single-phase power converter is a third-phase circuit in the power grid phase sequence.

[0152] The grid phase sequence determination method for power converters provided in this embodiment is applied to a second controller. The second controller acts as an on / off control device between each single-phase power converter and the corresponding phase circuit of the multi-phase power grid system. It receives relevant control signals from the first controller and controls one phase circuit in the multi-phase power grid system to connect to the corresponding single-phase power converter, while the remaining phase circuits are disconnected from the corresponding single-phase power converter. This allows the first controller to query the operating status of each single-phase power converter under this on / off state, thereby determining the grid phase sequence of each single-phase power converter, improving the accuracy of grid phase sequence determination, and increasing the grid connection efficiency of single-phase power converters.

[0153] In an exemplary embodiment, the second controller and each switch are housed within a relay. In an implementation where the multiphase power grid system is a three-phase power grid system, as shown in Figure 2, the first switch, the second switch, the third switch, and the switch controller are housed within a relay, and the first controller is a gateway controller; wherein, the first terminal of the first switch is connected to the gateway controller and the first phase circuit of the three-phase power grid system, and the second terminal of the first switch is connected to the single-phase power converter corresponding to the first phase circuit; the first terminal of the second switch is connected to the gateway controller and the second phase circuit of the three-phase power grid system, and the second terminal of the second switch is connected to the single-phase power converter corresponding to the second phase circuit; the first terminal of the third switch is connected to the gateway controller and the third phase circuit of the three-phase power grid system, and the second terminal of the third switch is connected to the single-phase power converter corresponding to the third phase circuit.

[0154] In this embodiment, the process of opening the remaining switches based on the first control signal includes: opening the second switch and the third switch based on the first control signal.

[0155] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0156] It is understood that the term "based on" as used in this disclosure is used to describe one or more factors that influence the determination, but does not exclude other factors that may influence the determination. For example, the phrase "determine A based on B" means that the determination of A can be based entirely or at least partially on factor B. That is, B is a factor that influences the determination of A, but does not exclude the fact that the determination of A is also based on C.

[0157] Based on the same inventive concept, this disclosure also provides a power grid phase sequence determination device for implementing the power grid phase sequence determination method for the power converter described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations in the embodiments of the power grid phase sequence determination device for one or more power converters provided below can be found in the limitations of the power grid phase sequence determination method for power converters described above, and will not be repeated here.

[0158] In an exemplary embodiment, a power converter grid phase sequence determination device is provided, used in a first controller, for identifying the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. The grid phase sequence determination device includes: an on / off control module, a status query module, and a phase sequence determination module, wherein:

[0159] The on / off control module is used to control the remaining phase circuits in the multiphase power grid system to disconnect from the corresponding single-phase power converters when all single-phase power converters are in the state of grid-connected power generation.

[0160] The status query module is used to send the first status query request to each single-phase power converter;

[0161] The phase sequence determination module is used to determine the phase sequence of the power grid as the target phase circuit single-phase power converter based on the first feedback information received corresponding to the first state query request.

[0162] The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, while the other phase circuits correspond to all phase circuits in the multiphase power grid system except for the target phase circuit.

[0163] In an exemplary embodiment, the communication method between the controller and each single-phase power converter includes wireless communication or power line carrier communication; the phase sequence determination module is used to determine the grid phase sequence of the single-phase power converter whose first feedback information includes first state information as the target phase circuit, and the first state information is used to indicate that the corresponding single-phase power converter is in the working state; and to determine the grid phase sequence of the single-phase power converter whose first feedback information includes second state information as not the target phase circuit, and the second state information is used to indicate that the corresponding single-phase power converter is not in the working state.

[0164] In an exemplary embodiment, the communication method between the controller and each single-phase power converter includes a one-to-one wired communication method; the phase sequence determination module is used to determine the grid phase sequence of the single-phase power converter that feeds back the first feedback information as the target phase circuit.

[0165] In an exemplary embodiment, the multiphase power grid system is a three-phase power grid system, the target phase circuit includes a first phase circuit, and the remaining phase circuits include a second phase circuit and a third phase circuit; the on / off control module is used to control the second phase circuit and the third phase circuit to disconnect from the corresponding single-phase power converter; the phase sequence determination module is used to determine the single-phase power converter of the first phase circuit according to the first feedback information.

[0166] In an exemplary embodiment, the on / off control module is further configured to control the connection of the second-phase circuit and the third-phase circuit with the corresponding single-phase power converter; when all single-phase power converters are in the state of grid-connected power generation, control the disconnection of the first-phase circuit and the third-phase circuit with the corresponding single-phase power converter; the status query module is further configured to send a second status query request to each single-phase power converter whose grid phase sequence is not the first-phase circuit; the phase sequence determination module is further configured to determine the single-phase power converter whose phase sequence is the second-phase circuit based on the second feedback information received corresponding to the second status query request.

[0167] In an exemplary embodiment, the on / off control module is further configured to control the connection of the first phase circuit and the third phase circuit with the corresponding single-phase power converter; when all single-phase power converters are in the state of grid-connected power generation, control the first phase circuit and the second phase circuit to disconnect from the corresponding single-phase power converter; the status query module is further configured to send a third status query request to each single-phase power converter whose grid phase sequence is not the first phase circuit or the second phase circuit; the phase sequence determination module is further configured to determine the single-phase power converter whose phase sequence is the third phase circuit according to the third feedback information received corresponding to the third status query request.

[0168] In an exemplary embodiment, the power grid phase sequence determination module is further configured to determine the power grid phase sequence of a single-phase power converter whose power grid phase sequence is not the first phase circuit or the second phase circuit as the third phase circuit.

[0169] In an exemplary embodiment, the status query module is further configured to send a fourth status query request to all single-phase power converters. If the first quantity equals the second quantity, it is determined that all single-phase power converters are in a grid-connected power generation state. The first quantity is the number of fourth feedback messages corresponding to the fourth status query request received within a preset time period, and the second quantity is the number of single-phase power converters connected to the three-phase power grid system. If the first quantity does not equal the second quantity, it is determined that not all single-phase power converters are in a grid-connected power generation state.

[0170] In an exemplary embodiment, a power grid phase sequence determination device for a power converter is provided. In a first controller, the first controller is connected to a second controller, which controls the on / off switching between corresponding phase circuits of each single-phase power converter and the multi-phase power grid system. The power grid phase sequence determination device is used to determine the power grid phase sequence of each single-phase power converter connected to a three-phase power grid system. The power grid phase sequence determination device includes: an on / off control module, a status query module, and a phase sequence determination module, wherein:

[0171] The on / off control module is used to send a first control signal to the second controller when all single-phase power converters are in the grid-connected power generation state. The first control signal is used to enable the second controller to open the remaining switches.

[0172] The status query module is used to send the first status query request to each single-phase power converter;

[0173] The phase sequence determination module is used to determine the phase sequence of the power grid as the target phase circuit single-phase power converter based on the first feedback information received corresponding to the first state query request.

[0174] Among them, the remaining switches are used to control the on / off state of the single-phase power converters and the remaining phase circuits corresponding to the remaining phase circuits in the three-phase power grid system. The target phase circuit corresponds to any one phase circuit in the multi-phase power grid system, and the remaining phase circuits correspond to the phase circuits in the multi-phase power grid system other than the target phase circuit.

[0175] In one exemplary embodiment, a power grid phase sequence determination device for a power converter is provided, used in a second controller. This device is used to determine the power grid phase sequence of each single-phase power converter connected to a multiphase power grid system. The device includes a signal receiving module and an on / off execution module, wherein...

[0176] The signal receiving module is used to receive the first control signal sent by the first controller when all single-phase power converters are in the state of grid-connected power generation.

[0177] The on / off execution module is used to execute the opening of the remaining switches based on the first control signal, so that the first controller can send a first state query request to each single-phase power converter when the target switch is closed and the remaining switches are open, and determine the single-phase power converter whose grid phase sequence is the target phase circuit based on the first feedback information corresponding to the received first state query request; wherein, the target switch is used to control the on / off of the single-phase power converter and the target phase circuit corresponding to the target phase circuit in the multiphase power grid system, and the remaining switches are used to control the on / off of the single-phase power converter and the remaining phase circuits corresponding to the remaining phase circuits in the multiphase power grid system. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the remaining phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit.

[0178] The various modules in the power grid phase sequence determination device of the aforementioned power converter can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in the network device, or stored in software in the memory of the network device, so that the processor can call and execute the corresponding operations of each module.

[0179] In one exemplary embodiment, a first controller is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above embodiments of the power grid phase sequence determination method for the first controller.

[0180] In one exemplary embodiment, the provided first controller includes a switching module, wherein the processor is configured to control the remaining phase circuits to disconnect from the corresponding single-phase power converter via the switching module.

[0181] In an exemplary embodiment, the provided first controller is connected to the second controller, and the process of the processor disconnecting the remaining phase circuits in the multiphase power grid system from the corresponding single-phase power converter includes: the processor sending a first control signal to the second controller, the first control signal being used by the second controller to open the remaining switches.

[0182] In one exemplary embodiment, a second controller is provided. The second controller includes a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps described in the embodiments of the power grid phase sequence determination method for the second controller.

[0183] In one exemplary embodiment, a relay is provided, which includes a second controller and switches provided in the above embodiments.

[0184] In an exemplary embodiment, a power system is provided, referring to FIG2. The power system includes: a plurality of single-phase power converters, a relay, and a first controller; wherein, the first terminal of the first switch in the relay is connected to the first controller and a target phase circuit for connecting a multiphase power grid system, the second terminal of the first switch is connected to the single-phase power converter corresponding to the target phase circuit, the first terminals of the remaining switches in the relay are connected to the first controller and the remaining phase circuits for connecting a multiphase power grid system, the second terminals of the second switches are connected to the single-phase power converters corresponding to the remaining phase circuits, the first controller includes a memory and a processor, the memory stores a computer program, and the processor executes the computer program to implement the steps in the above embodiments of the power grid phase sequence determination method for the power converters in the first controller.

[0185] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the above method embodiments.

[0186] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0187] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this disclosure are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0188] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, databases, or other media used in the embodiments provided in this disclosure can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this disclosure may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this disclosure may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0189] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0190] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the scope of protection of this disclosure. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method of grid phase sequence determination for a power converter, wherein, The method is used in a first controller, and the method is used to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system; the method includes: When all the single-phase power converters are in the grid-connected power generation state, the remaining phase circuits in the multi-phase power grid system are disconnected from the corresponding single-phase power converters. Send a first status query request to each of the single-phase power converters; Based on the first feedback information received corresponding to the first status query request, the single-phase power converter of the target phase circuit is determined to be the phase sequence of the power grid. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the remaining phase circuits correspond to all phase circuits in the multiphase power grid system except for the target phase circuit.

2. The method of claim 1, wherein, The communication method between the first controller and each of the single-phase power converters includes wireless communication or power line carrier communication. The step of determining the grid phase sequence of the single-phase power converter as the target circuit based on the received first feedback information corresponding to the first state query request includes: The grid phase sequence of the single-phase power converter, which includes the first state information in the first feedback information, is determined as the target phase circuit. The first state information is used to indicate that the corresponding single-phase power converter is in the working state. The grid phase sequence of the single-phase power converter, which includes the second state information in the first feedback information, is determined to be not the target phase circuit. The second state information is used to indicate that the corresponding single-phase power converter is not in operation.

3. The method of claim 1, wherein, The communication method between the first controller and each of the single-phase power converters includes a one-to-one wired communication method; The step of determining the grid phase sequence of the target phase circuit based on the first feedback information received corresponding to the first state query request for a single-phase power converter includes: The grid phase sequence of the single-phase power converter that feeds back the first feedback information is determined as the target phase circuit.

4. The method according to any one of claims 1 to 3, wherein, The multiphase power grid system is a three-phase power grid system, the target phase circuit includes a first phase circuit, and the remaining phase circuits include a second phase circuit and a third phase circuit; The step of controlling the remaining phase circuits in the multiphase power grid system to disconnect from the corresponding single-phase power converters includes: controlling the second phase circuit and the third phase circuit to disconnect from the corresponding single-phase power converters; The step of determining the grid phase sequence of the target phase circuit based on the first feedback information received corresponding to the first state query request for a single-phase power converter includes: Based on the first feedback information, the power grid phase sequence is determined to be the single-phase power converter of the first phase circuit.

5. The method of claim 4, wherein, After the step of determining the single-phase power converter of the target phase circuit based on the first feedback information received corresponding to the first status query request, the method further includes: Control the connection of the second phase circuit and the third phase circuit to the corresponding single-phase power converter; When all the single-phase power converters are in the grid-connected power generation state, the first phase circuit and the third phase circuit are disconnected from the corresponding single-phase power converters. Send a second state query request to each of the single-phase power converters whose grid phase sequence is not the first phase circuit; Based on the second feedback information received corresponding to the second status query request, the power grid phase sequence is determined to be the single-phase power converter of the second phase circuit.

6. The method of claim 5, wherein, After the step of determining the power grid phase sequence of the single-phase power converter as the second phase circuit based on the second feedback information received corresponding to the second status query request, the method further includes: Control the connection of the first phase circuit and the third phase circuit to the corresponding single-phase power converter; When all the single-phase power converters are in the grid-connected power generation state, the first phase circuit and the second phase circuit are disconnected from the corresponding single-phase power converters. Send a third state query request to each of the single-phase power converters whose grid phase sequence is not the first phase circuit and the second phase circuit; Based on the third feedback information received corresponding to the third state query request, the power grid phase sequence is determined to be the single-phase power converter of the third phase circuit.

7. The method of claim 5 or 6, wherein, After the step of determining the power grid phase sequence of the single-phase power converter as the second phase circuit based on the second feedback information received corresponding to the second status query request, the method further includes: The grid phase sequence of a single-phase power converter whose grid phase sequence is not the first phase circuit or the second phase circuit is determined as the third phase.

8. The method of any one of claims 1-7, wherein, To determine whether all of the single-phase power converters are in a grid-connected power generation state, follow these steps: Send a fourth state query request to all of the single-phase power converters; If the first quantity equals the second quantity, then all the single-phase power converters are determined to be in the grid-connected power generation state; the first quantity is the number of fourth feedback messages corresponding to the fourth state query request received within a preset time period, and the second quantity is the number of single-phase power converters connected to the multiphase power grid system; If the first quantity is not equal to the second quantity, then it is determined that not all of the single-phase power converters are in a grid-connected power generation state.

9. A method of grid phase sequence determination for a power converter, wherein, The method is used in a first controller, which is communicatively connected to a second controller. The second controller is used to control the on / off switching between corresponding phase circuits of each single-phase power converter and the multiphase power grid system. The method is used to determine the power grid phase sequence corresponding to each single-phase power converter connected to the multiphase power grid system. The method includes: When all the single-phase power converters are in the grid-connected power generation state, a first control signal is sent to the second controller. The first control signal is used to enable the second controller to turn on the remaining switches. Send a first status query request to each of the single-phase power converters; Based on the first feedback information received corresponding to the first status query request, the single-phase power converter of the target phase circuit is determined to be the phase sequence of the power grid. The remaining switches are used to control the on / off state of the single-phase power converters corresponding to the remaining phase circuits in the multiphase power grid system and the remaining phase circuits. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the remaining phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit.

10. A method of grid phase sequence determination for a power converter, wherein, The method is used in a second controller, which controls the on / off switching between corresponding phase circuits of each single-phase power converter and the multiphase power grid system. The method is used to determine the grid phase sequence corresponding to each single-phase power converter connected to the multiphase power grid system. The method includes: When all the single-phase power converters are in the grid-connected power generation state, the first control signal sent by the first controller is received; Based on the first control signal, the remaining switches are opened so that when the target switch is closed and the remaining switches are open, the first controller sends a first status query request to each of the single-phase power converters and determines the single-phase power converters of the target phase circuit based on the first feedback information corresponding to the received first status query request. The target switch is used to control the on / off state of the single-phase power converter corresponding to the target phase circuit in the multiphase power grid system and the target phase circuit. The other switches are used to control the on / off state of the single-phase power converter corresponding to the other phase circuits in the multiphase power grid system and the other phase circuits. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the other phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit.

11. A first controller comprising a memory and a processor, the memory storing a computer program, wherein, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 9.

12. The first controller of claim 11, wherein, The first controller includes a switching module. The process by which the processor controls the remaining phase circuits in the multiphase power grid system to disconnect from the corresponding single-phase power converter includes: the processor controlling the remaining phase circuits to disconnect from the corresponding single-phase power converter through the switching module.

13. A second controller comprising a memory and a processor, the memory storing a computer program, wherein, When the processor executes the computer program, it implements the steps of the method of claim 10.

14. An electric power system, wherein, The power system includes: multiple single-phase power converters, relays, and a first controller; wherein... The first terminal of the target switch in the relay is connected to the controller and the target phase circuit for connecting the multiphase power grid system. The second terminal of the target switch is connected to the single-phase power converter corresponding to the target phase circuit. The first terminals of the remaining switches in the relay are connected to the first controller and the remaining phase circuits for connecting the multiphase power grid system. The second terminals of the remaining switches are connected to the single-phase power converters corresponding to the remaining phase circuits. The target phase circuit corresponds to any one phase circuit in the multiphase power grid system, and the remaining phase circuits correspond to the phase circuits in the multiphase power grid system other than the target phase circuit. The first control includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method according to any one of claims 1 to 9.

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